• Bulletin of the Korea Photovoltaic Society
• /
• v.6 no.1
• /
• pp.86-91
• /
• 2020

Nepal is among the richest in terms of water resource availability and it is one of the most important natural resources of the country. Currently, 72% of the population is electrified through the national grid system. The power generation mix into the grid is hydro dominated with minor shares generated from solar and thermal (accounts for less than 1%). To achieve sustainable development in the power sector it is essential to diversify power generation mix into the grid. Knowing the facts, the government has a plan to achieve a 5-10% share of power generation from solar and mix it into the grid system. Solar is the second most abundant, prominent and free source of renewable in the context of Nepal. This study mainly focuses on the grid-connected solar system, its importance, present status, government efforts, and its need. It is based on the review of literature, news published in national newspaper online news and international organization's report.

• Proceedings of the KIPE Conference
• /
• 2010.07a
• /
• pp.216-217
• /
• 2010

This paper presents a new software-based on-line dead-time compensation technique for single-phase grid-connected photovoltaic (PV) inverter system. To improve the mitigation of dead-time effect around the zero-crossing point of phase current, a selective harmonic elimination of instantaneous feedback current is used as an additional part of conventional current control scheme. Simulation and experimental results are shown to verify the effectiveness of proposed compensation method in the grid-connected power distributed generation systems.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.16 no.4
• /
• pp.451-462
• /
• 2016

Photovoltaic energy conversion becomes main focus of many researches due to its promising potential as source for future electricity and has many advantages than the other alternative energy sources like wind, solar, ocean, biomass, geothermal etc. In Photovoltaic power generation multilevel inverters play a vital role in power conversion. The three different topologies, diode-clamped (neutral-point clamped) inverter, capacitor-clamped (flying capacitor) inverter and cascaded h-bridge multilevel inverter are widely used in these multilevel inverters. Among the three topologies, cascaded h-bridge multilevel inverter is more suitable for photovoltaic applications since each pv array can act as a separate dc source for each h-bridge module. This paper presents a single phase Cascaded H-bridge five level inverter for grid-connected photovoltaic application using sinusoidal pulse width modulation technique. This inverter output voltage waveform reduces the harmonics in the generated current and the filtering effort at the input. The control strategy allows the independent control of each dc-link voltages and tracks the maximum power point of PV strings. This topology can inject to the grid sinusoidal input currents with unity power factor and achieves low harmonic distortion. A PID control algorithm is implemented in Arm Processor LPC2148. The validity of the proposed inverter is verified through simulation and is implemented in a single phase 100W prototype. The results of hardware are compared with simulation results. The proposed system offers improved performance over conventional three level inverter in terms of THD.

• Proceedings of the KIEE Conference
• /
• 2001.10a
• /
• pp.296-300
• /
• 2001

Novel concept of shunt active filter (AF) function added in Photovoltaic (PV) generation system is described in this paper. So far, for the PV generation system has been treated as one of harmonic sources to the power distribution systems, not only a PV system combined with AF but also AF systems using PV module as their power source have never been discussed. The basic structure and control strategy of the PV-AF system are, for the first time, introduced in this work. In order to stabilize the output current of voltage source inverter (VSI), the reference voltage MPPT control is applied. Simulation analysis shows that it is possible to combine AF function to the three-phase grid-connected PV generation system without any physical difficulties, and the performance of the proposed PV-AF system is acceptable and stable as well.

• Proceedings of the KIEE Conference
• /
• 2005.07b
• /
• pp.1687-1689
• /
• 2005

In this paper, novel concept of a photovoltaic(PV) power generation system adding the function of active filter(AF) is proposed. Even PV power generation system can be treated to a harmonics source for the power distribution system, it is necessary that the function of AF system in grid connected PV power generation system. Active Filters intended for harmonic solutions are expending their functions from harmonic compensation of nonlinear loads into harmonic isolation between utilities and consumer, and harmonic damping throughout power distribution system. So, the PV system combined the function of AF system can be usefully applied in power distribution system. Here, the control strategy of PV-AF system is introduced.

• Proceedings of the KIPE Conference
• /
• 2013.07a
• /
• pp.130-131
• /
• 2013

In this paper, it suggests offset compensation method of output current in single phase PV-BES system which is connected with grid. The algorithm applied removes grid's frequency ingredient using a notch filter and it extracts only DC offset current. It can reduce problems as saturation of power transformer cause by DC current when it is indoctrinated to grid.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.10
• /
• pp.590-597
• /
• 2018

Recently, the installation of PV systems has been increasing due to the worldwide interest in eco-friendly and renewable solar energy. On the other hand, the output power of PV systems is influenced strongly by the surrounding weather conditions. In addition, the entire operation efficiency of PV systems may be decreased considerably even if only some of the PV modules are in the shade. In other words, the existing control method at which strings with modules in series are connected to an inverter may be not operated in the case that the string voltage in partial shade is lower than the operating range of the grid connected inverter. To overcome these problems, this paper proposes an operation efficiency improvement device of a PV system using a Li-ion battery, which can compensate for the voltage of each string in the PV system when it is partially shaded. In addition, this paper presents the modeling of the operation efficiency improvement device, including PV strings, Li-ion battery and a 3-Phase grid inverter based on the PSIM S/W. From the simulation results, it was confirmed that the proposed control method can improve the operating efficiency of PV systems by compensating for the string voltage with partial shade.

• Proceedings of the KIEE Conference
• /
• 2003.07b
• /
• pp.1353-1355
• /
• 2003

Total six units of 3kW photovoltaic (PV) system and data acquisition system (DAS) are constructed for analyzing performance of PV system at field demonstration test center of Gwang-Ju in Korea. As climatic and irradiation conditions are varied, operation characteristics of the PV system are collected and analyzed in data-acquisition system. Furthermore, not only performance test of each PV system component such as PV module and power conditioning system, but also performance of total PV system e.g. system efficiency, electric power and loss factor at the site are reviewed.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.6 no.2
• /
• pp.309-314
• /
• 2002

New grid connected PV(Photovoltaic) system of high-frequency link with soft-switching is proposed to solve problems related to the loss of transformer and switch. The operation of Proposed system using the soft switching that consists of high frequency transformer is confirmed by computer simulation and experiment. It can improve its efficiency and solve the Problems mentioned above.

• Journal of Electrical Engineering and Technology
• /
• v.13 no.2
• /
• pp.742-751
• /
• 2018

Electric vehicles (EV) are emerging as the future transportation vehicle reflecting their potential safe environmental advantages. Vehicle to Grid (V2G) system describes the hybrid system in which the EV can communicate with the utility grid and the energy flows with insignificant effect between the utility grid and the EV. The paper presents an optimal power control and energy management strategy for Plug-In Electric Vehicle (PEV) charging stations using Wind-PV-FC-Battery renewable energy sources. The energy management optimization is structured and solved using Multi-Objective Particle Swarm Optimization (MOPSO) to determine and distribute at each time step the charging power among all accessible vehicles. The Model-Based Predictive (MPC) control strategy is used to plan PEV charging energy to increase the utilization of the wind, the FC and solar energy, decrease power taken from the power grid, and fulfil the charging power requirement of all vehicles. Desired features for EV battery chargers such as the near unity power factor with negligible harmonics for the ac source, well-regulated charging current for the battery, maximum output power, high efficiency, and high reliability are fully confirmed by the proposed solution.